The purpose of this investigation is to utilize mfMRI sequences to identify and evaluate swallowing muscles and the various rehabilitative techniques that exercise them. Rehabilitative swallowing exercises are designed to strengthen specific muscles that execute particular biomechanical events. Furthermore, for an exercise to be effective, the exercise should induce greater muscle contraction than with regular use. This is called the principle of overload. The current problem to be solved is that the muscles used in swallowing have not been thoroughly investigated and verified. We propose that mfMRI can be used to verify the muscles used in swallowing, and also to evaluate rehabilitative swallowing exercises in terms of their specificity and ability to achieve overload. To achieve this purpose we propose to: 7 Obtain structural data of the swallowing apparatus by using anatomical and dynamic MRI sequences to map key anatomical landmarks and constrain reliable regions of interest of swallowing muscles as a reference point for identifying muscles in mfMRI. 7 Document the activation of swallowing muscles using mfMRI. To do this we will first verify the ability mfMRI to identify muscles activated in the head and neck region by testing the muscles of mastication, which are more easily identified. We will then compare swallowing muscles that are active versus at rest in mfMRI. Finally we will develop a rudimentary atlas of regions of interest representing muscles utilized in swallowing. 7 Determine if the Shaker, Mendelshon, and Effortful Swallow rehabilitative techniques are effective swallowing therapies by testing if these exercise use the same specific muscles used in swallowing and if they are used to a greater degree in exercise than in regular use. In strength training this is known as the principles of specificity and overload. Unique to this proposal is the use of mfMRI as an assessment of the anatomical structure underlying swallowing function and the exercises that are designed to rehabilitate them. PUBLIC HEALTH RELEVANCE: Favorable swallowing is an important quality of life issue. Swallowing specialists work with patients to improve swallowing ability through rehabilitative exercises. However, current methods used to evaluate the musculature underlying swallowing and swallowing therapies are limited. This project will develop the application of muscle functional MRI as a methodology to investigate muscle function underlying swallowing and to evaluate the exercises designed to improve swallowing function. !